Exhaustive laboratory and clinical trials and precise understanding of intramuscular microcirculation and the process of motor re-innervation, have provided a new dimension to the skeletal muscle being transferred as Free Functioning muscle transfers (FFMT). FFMT have provided an unlimited option in restoration of function in some of the difficult Reconstructive Problems of Upper Extremity; like Brachial Plexus Injuries, Post-Polio Paralysis, Proximal and Extensive Soft Tissue Tumor Resection compromising the functional status of the Extremity seriously, Post-Traumatic / Post-Infective loss or Ischaemic Contracture of Muscles.
For being able to perform a successful Free Functioning muscle transfers (FFMT), it is mandatory to provide the transplanted muscle a suitable and adequate source for motor innervation. The transplanted muscle should provide adequate strength of contraction and adequate range of motion to be able to achieve the desired function. In order to replace the long flexors of the finger, a range of motion of 6.0 – 7.0 cms must be obtained following Free Functioning muscle transfer. As the total amount of muscle contraction is proportional to the length of the individual muscle fiber, a strap muscle will contract more than a pinnate muscle. Following Free Functioning muscle transfer, if the muscle is positioned at a tension that is slightly too tight or too loose, a portion of the useful range of contraction may be out of the Range of Motion of the particular joint. Hence, for Free Functioning muscle transfer, a muscle has to be chosen, which has a greater range of motion at its pre-transfer normal site than what will be desired at the transplanted site.
The Gracillis muscle has a single nerve composed of two to six fascicles. The distance of the nerve anastomosis from the neuromuscular junction should be minimized and preferably should be kept to 2.0 cm or less. Two-team approach is advocated, one each for the recipient and donor site respectively. At the recipient site the distal end of Sural nerve graft is identified and prepared and so are the recipient vessels, while the other team prepares the donor muscle on its neuro-vascular pedicle. The donor muscle neuro-vascular pedicle should be divided only when recipient site is ready, as the warm ischaemia time of muscle is short. Transfixing stitches to be used for insertion of donor muscle at the recipient site is kept ready in place.
Secondary microsurgical reconstructions in pre-ganglionic or global Brachial Plexus lesions, utilizing adjoining or distant motor nerves and functioning muscle transfers have added a number of possibilities for a useful rehabilitation program. Time interval between injury and secondary surgical repair do not influence the outcome significantly. These procedures aimed at providing: